KEN JENNINGS WILL admit that during his record-setting Jeopardy! run of 74 straight wins in 2004, he lied to Alex Trebek. It was about airline food. The host was interviewing him after the show's first commercial break, and by that point — Ken Jennings can't remember exactly when it was, at what point in the 1,800 minutes or so of airtime he occupied — but by that point, Ken Jennings had affably surrendered just about all of the harmless personal factoids he had to offer. So Ken Jennings told Alex Trebek that he liked airline food.

Ken Jennings told Alex Trebek that he liked airline food, even though he doesn't, or more accurately, even though he doesn't have an opinion on it one way or another, because Ken Jennings understood the rhythm of the Jeopardy! dance: Liking airline food is peculiar; liking airline food would be fodder for that signature Alex Trebek brand of humor, half eye-rolling dismissal and half knowing nod to the audience — like, of course he likes airline food, folks, this is a Jeopardy! contestant. And sure enough, Alex Trebek raised his eyebrows at Ken Jennings, Ken Jennings further sculpted his role as the goofy savant who'd become Alex Trebek's foil, and the most memorable stint in the history of American game shows rolled on.

On Jeopardy!, knowledge begets money, but the money is beside the point, just a unit of scorekeeping. The contestants themselves are usually beside the point too, those personal anecdotes taking up no more than 10 percent of the show, the rest reserved for a game of the mind — unusual in an America gleefully painted by itself and the rest of the world as a greedy, anti-intellectual society. It isn't reality TV, no personalities or rivalries, just a few good strivers engaging in brain competition, and you at home playing along with them. Jeopardy! is both elitist and all-inclusive. Alex Trebek is its nominal star, but the real star is the idea that being smart alone is worth something, even if you're the kind of social oddball who likes airline food.

Ken Jennings transcended the show by being the epitome of the show. Jennings — Ken Jennings to America, that type of name you can't help but pronounce in full, to the extent that even his then 2-year-old son would call him Ken Jennings during his six-month run — became a celebrity in a celebrity-free zone.

Jennings, the onetime programmer of health-care software, is taking advantage of your familiarity to this day, publishing nonfiction books, writing a weekly news quiz for Slate, writing a weekly column about obscure world destinations for Condé Nast Traveler, debunking myths for Woot.com, creating a trivia puzzle for Parade magazine and one-offs for sites like ESPN's Grantland, tweeting a handful of times a day, and doing whatever else he can to keep rolling in his career as a professional smart person. Don't let the clean-cut Mormon good looks or aw-shucks demeanor fool you: Ken Jennings is on the grind.

I MEET JENNINGSin a coffee shop in New York City, a continent away from his home in Seattle, where he lives with his wife, Mindy, and two children. He is here to promote his new book, Because I Said So, the fourth he's written since his $2,522,700 in winnings allowed him to quit his job as a software engineer. His current job description is emblematic of the social media age: Being himself, for fun and profit. Which means being more than a little self-aware.

"I sort of peaked before I was 30," he says, laughing. "It's already guaranteed that it'll say Jeopardy! on my tombstone."

Jennings partly credits his talent for memorizing cultural bullet points to a quirk of biography. His family lived in the Seattle area until Ken was in first grade, when Jennings's father, a lawyer, moved them to Seoul. Originally planning to stay for two years, they stuck around for 11, with Ken eventually graduating from Seoul Foreign School. Growing up abroad, Jennings became obsessed with any artifacts of American culture that would make their way into Seoul; he and his classmates, expat children and military kids, would copy and share cassette tapes and figure out how to see Back to the Future when it showed on the Army base.

Jennings was also taking cues from his parents, the type of people who kept reference books around the house, smart folks who were told by their friends they would create a super race if they reproduced. On rainy days, Jennings would sit around and use the books to build a connection between himself and his home country, studying, for example, local road maps of Delaware. Since childhood, he says, he has tended to index new facts geographically, so that his knowledge ends up clustered around locations — the first thing he'll remember about a person is where they're from, and the first thing he'll remember about an event is where it took place.

After initially pursuing an English major at Brigham Young, Jennings switched to computer science. The dot-com boom made it very easy for him to work for a classmate's start-up. By graduation in 2000, he'd already become engaged to Mindy, who majored in theater and worked as a preschool teacher after BYU.

Mindy, who spoke with me by phone from Seattle, said that her husband never tried to give off the impression of intelligence back in college. (He also — fun fact — took nine months to ask Mindy out after announcing to her roommate his intention to do so.) "He mostly wanted people to know he was funny," she said. "He's not the type of person who wants you to know he knows everything."

IT'S CLEAR THAT Jennings doesn't view himself as an intellectual in the traditional sense, and this partly explains why he's been able to endure without the show. He's a product of pop culture who happens to know all the roads in Delaware. "For so long, I was always the guy in the office who you could ask the name of a TV show or guys in a band, but that's not really valuable in the Google age," Jennings says. "I'd always been good at that, but I turned my back on it because I didn't really think I could make a living that way. I thought being a programmer was a safe thing to do, and by accident, I became much more successful doing what I was actually good at."

Jennings's post-Jeopardy! years as a professional whiz have coincided with the general triumph of geek culture. He's obviously not one to miss such a thing. "There's this idea of the jocks vs. nerds thing. That sort of ended when the nerds won decisively. We now live in this era where your big summer tentpole movies can be hobbits and minor Marvel Comics superheroes and boy wizards. If you had told me when I was in junior high there would be a $200 million movie about Hawkeye and Black Widow, I'd be like, 'Hawkeye — that guy's lame!'" Jennings says. "Those nerds started running Hollywood studios, and our captains of industry became Asperger types with acne scars."

After the show ended, Jennings got an agent and a book deal, and once the book deal was in place, he quit his job, freed by the Jeopardy windfall to return to doing what he was "actually good at." His first two books, Brainiac and Ken Jennings's Trivia Almanac, were very much products of Jeopardy Champion Ken Jennings, dealing directly with facts. With his third book, Maphead, about — yes — maps, Jennings started dealing with the way we perceive and represent facts, specifically geographical ones, though in a much less academic way than I've just made it sound.

His new book, Because I Said So, is a natural evolution for him: It's a case-by-case investigation of time-honored clichés passed down by parents to their children that attempts to prove or disprove those weird half-truths of childhood (i.e., don't look in the microwave, don't cross your eyes, the five-second rule). He crowd-sourced some of the clichés themselves, asking for submissions on Reddit, which supplied him with a couple dozen aphorisms. He did the legwork himself, figuring out which ideas had some basis in truth (double-dipping does spread germs) and which were verifiably false (you don't need eight glasses of water a day).

His utilization of Reddit demonstrates Jennings's understanding of the Internet community, both on its own merits and as the world's best PR firm. And he's really taken to Twitter. Part of his bio reads, "Your grandma loves/hates him because he was on Jeopardy for a long time," and his banter is fully versed in the slightly-off cadences of the medium. Jennings walks the balance beam of openness and insularity, exhibiting some techniques of quote-unquote Weird Twitter, while still making jokes about his children and Mitt Romney.

When I ask Jennings if he considers himself a comedian, he demurs — "Twitter makes you a comedian in the same way that digital cameras make you a photographer" — but it's clear that he spends time thinking about the mechanics of comedy. He cites Spy magazine — a wit-driven New York publication that existed from 1986 through 1998 and was probably not broadly read among churchgoing Mormons of his generation — as an influence. Mindy told me he'd discussed writing a book about comedy, which would seem to fit his M.O. Rather than functioning as a reporter or a critic, Jennings seems to be more like the world's greatest tour guide: He leads his readers through subjects, informing and entertaining them along the way, and then drops them off at the end feeling like they've accomplished something.

JENNINGS HAS RETURNEDto the show for various Jeopardy! Tournaments of Champions and a slightly more symbolic test two years ago, in which he squared off against Watson, a trivia supercomputer developed by IBM. He came in second place over a two-day contest, with fellow former champion Brad Rutter coming in third, neither able to quite top the computer's combination of speed and depth of knowledge, though both say they think they could have.

"I really do think it meant something," he says. "I think it's very meaningful that when people would talk about the Watson match, they would always make jokes about HAL or Skynet in Terminator or The Matrix, all the touchstones where the evil machines were going to replace us. IBM would be like, 'No, no, no, it's the helpful computer from Star Trek,' and people would be like, 'Whatever, it's HAL.' I feel like that must be a sign of something deep-rooted: We are worried about being replaced. And I felt that personally. Being the guy who got replaced, not just the competitor wanting to win, that was also, 'Wow, the only thing I'm really good at IBM duplicated in 18 months by throwing a few million dollars at it.'"

In his dystopian future, nerds are replaced by better robot nerds — nerds without joy and humor and enthusiasm. And I suppose that maybe someday Watson will be engineered into the Perfect Nerd. But it will be tough to beat Ken Jennings.